Locking mechanism for telescopically adjustable extension pole

ABSTRACT

A locking mechanism for a telescopically adjustable extension pole is disclosed. The locking mechanism includes a collar member and a locking trigger mechanism preferably comprising a bottom trigger member and a top trigger member having a locking pin therein. The top trigger member grippingly engages the collar member which is attached to the outer sleeve of the pole. By depressing the bottom trigger member, the top trigger member moves laterally outwardly retracting the locking pin from an aperture in the inner sleeve permitting the length of the extension pole to be telescopically adjusted. By releasing the bottom trigger member, the top trigger member moves laterally inwardly causing the locking pin to be received within an aperture in the inner sleeve so as to interlock the inner sleeve within the outer sleeve at the approximate desired length of the extension pole.

TECHNICAL FIELD

[0001] The present invention relates, in general, to an adjustableextension pole and, more particularly, to an improved locking mechanismfor a telescopically adjustable extension pole.

BACKGROUND ART

[0002] There are numerous types of extension poles that can be used forpainting or other applications, e.g., sweeping attachments, swimmingpool cleaning nets, and which allow the user to adjust the overalllength thereof. For example, such poles permit the attachment of a paintroller frame to the end thereof allowing the painter to paint walls andceilings without the use of a ladder. Such poles typically utilizetelescoping members for length adjustment purposes and some type oflocking mechanism to interlock the telescoping members after the desiredlength of the pole has been attained. It has been found that theselocking mechanisms usually have some type of inherent structural oroperational disadvantages. For example, the adjustable extension poledisclosed in U.S. Pat. No. 5,220,707 (Newman, Sr., et al.) utilizes alocking mechanism comprising a Belleville-type washer arrangement whichis connected to a pin which interlocks the outer telescoping sleevewithin the inner telescoping sleeve. By depressing a push buttonoperatively connected to the Belleville-type washer, the washer isdeformed causing the pin to be withdrawn from the inner sleevepermitting the inner sleeve to be telescopically adjusted within theouter sleeve. Operationally, the aforementioned locking mechanism hassome inherent disadvantages since, through use, the washer becomesfatigued causing the locking mechanism to malfunction. In addition,since a push button arrangement is used, paint can be easily entrappedunder and around same affecting the “snap-action” ability of theBelleville-type washer.

[0003] Another tube or sleeve locking mechanism is disclosed in U.S.Pat. No. 3,596,946 (Burton, et al.) which utilizes an unidirectional camlock arrangement to interlock the sleeves after the desired length ofthe extension pole has been attained. In this case, the inner and outersleeves must be properly aligned in order to operate the cam lockingarrangement and the cam locking arrangement is susceptible to paintbecoming entrapped therein causing the malfunction of same. Another tubeor sleeve locking mechanism is disclosed in U.S. Pat. No. 4,662,771(Roe, et al.). In this case, the locking mechanism is comprised of arelatively complex ball and detent arrangement received between machinedsleeves connected to the extension pole. The ball and detent arrangementis relatively costly to produce, and the resulting locking mechanism issusceptible to paint being entrapped therein resulting in the possiblemalfunction of same. A further tube or sleeve locking mechanism isdisclosed in U.S. Pat. No. 3,603,623 (Widman). This locking mechanismutilizes oppositely wound coil springs which surround the inner tubularsleeve. By changing the bias on the springs which can be accomplished bymoving external knobs on the outer surface of the locking mechanism, theinner sleeve is released permitting its telescopic adjustment within theouter sleeve. In this case, the coil springs are subject to fatigue andbreakage, and the locking mechanism is susceptible to paint beingentrapped therein due to its use of external knobs to change the bias onthe springs within same. Lastly, U.S. Pat. No. 5,288,161 (Graves, etal.) discloses a locking mechanism which interlocks the end of anextension pole to the end of a paint roller frame. In this case, theextension pole is not telescopically adjustable, however, the lockingmechanism permits the attachment of the pole, which can be any length,to the end of the paint roller frame. The locking mechanism disclosed inthis patent is comprised of a lever arrangement which is external to theend of the pole, and thus, is very susceptible to paint being entrappedtherein causing the locking mechanism to become difficult to operate orinoperable.

[0004] Because of the foregoing inherent disadvantages associated withpresently available extension poles, it has become desirable to developan extension pole locking mechanism that is durable, is easy to produce,assemble and operate and which is not susceptible to paint beingentrapped therein.

SUMMARY OF THE INVENTION

[0005] The present invention solves the problems associated with priorart extension poles and other problems by providing an extension polelocking mechanism which comprises a minimum number of components, isless susceptible to paint being entrapped therein, and is extremelysimple to produce and operate. The locking mechanism of the presentinvention comprises an outer tubular sleeve, an inner tubular sleevereceived within the outer tubular sleeve and a collar assembly attachedto the outer tubular sleeve. The collar assembly comprises a collarmember attached to the outer tubular sleeve and a locking triggermechanism which is received over the collar member and includes a bottomtrigger member and a top trigger member having a locking pin therein.The top trigger member has a circular configuration and grippinglyengages the collar member. The bottom trigger member has a U-shapedconfiguration and interlocks with the top trigger member. Because of theU-shaped configuration of the bottom trigger member, when the top andbottom trigger members are interlocked, a gap is created between theinner surface of the bottom trigger member and the collar member. Bydepressing the bottom trigger member, the gap between the bottom triggermember and the collar member closes causing the top trigger member tomove laterally outwardly retracting the locking pin from the innertubular sleeve permitting the length of the extension pole to beadjusted. After the desired length of the pole has been attained, ifpressure is released on the bottom trigger member, the top triggermember will move laterally inwardly causing the locking pin therein tobe received in an aperture in the inner tubular sleeve locking the innertubular sleeve within the outer tubular sleeve at the approximatedesired length of the extension pole.

[0006] Accordingly, it is an object of the present invention to providean extension pole locking mechanism which utilizes a minimum number ofcomponents.

[0007] Another object of the present invention is to provide anextension pole locking mechanism which is less susceptible to paintbeing entrapped therein.

[0008] A still another object of the present invention is to provide anextension pole locking mechanism that is durable.

[0009] A further object of the present invention is to provide anextension pole locking mechanism that is relatively inexpensive toproduce and is easy to assemble.

[0010] A still further object of the present invention is to provide anextension pole locking mechanism that can be easily replaced, ifnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is an exploded perspective view of an extension poleutilizing the locking mechanism of the present invention.

[0012]FIG. 2 is a cross-sectional view of one end of the extension poleillustrated in FIG. 1 and shows the attachment of the outer sleeve ofthe pole to the collar assembly utilizing the locking mechanism of thepresent invention.

[0013]FIG. 3 is a perspective view of the bottom trigger member of thecollar assembly shown in FIGS. 1 and 2.

[0014]FIG. 4 is a right end elevational view of the bottom triggermember of the collar assembly shown in FIGS. 1 and 2.

[0015]FIG. 5 is a perspective view of the top trigger member of thecollar assembly shown in FIGS. 1 and 2.

[0016]FIG. 6 is another perspective view of the top trigger member ofthe collar assembly shown in FIGS. 1 and 2.

[0017]FIG. 7 is an enlarged cross-sectional view of the collar assemblyshown in FIGS. 1 and 2.

[0018]FIG. 8 is a side elevational view, partially broken away incross-section, of an alternate embodiment of a collar assembly includinga unitary trigger member.

[0019]FIG. 9 is a cross-sectional view taken across section-indicatinglines 9-9 in FIG. 8.

[0020]FIG. 10 is a side elevational view of the alternate embodiment ofthe present invention shown in FIG. 7 and illustrates the lockingmechanism in an engaged or locked condition.

[0021]FIG. 11 is a side elevational view of the alternate embodiment ofthe present invention shown in FIGS. 7 and 10 and illustrates thelocking mechanism in a disengaged or unlocked condition permitting theadjustment of the overall length of the extension pole.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] Referring now to the drawings where the illustrations are for thepurpose of describing the preferred embodiment of the present inventionand not intended to limit the invention described herein, FIG. 1 is anexploded perspective view of a telescopically adjustable extension pole10 utilizing the sleeve locking mechanism of the present invention.Extension pole 10 is comprised of an outer tubular sleeve 12 having agrip 14 at one end thereof and a collar assembly 16 at the opposite endthereof, and an inner tubular sleeve 18 received within the outertubular sleeve 12. The inner tubular sleeve 18 has an end cap 20attached to one end thereof and a threaded connector 22 attached to theopposite end thereof.

[0023] The outer tubular sleeve 12 can be fabricated from a metallic ora non-metallic material, such as nylon or the like. If a nylon materialis utilized, fiberglass can be added to same to increase strength. Thegrip 14 has an inner diameter slightly less than the outer diameter ofouter tubular sleeve 12 permitting grip 14 to be slip fit over end 30 ofouter tubular sleeve 12 and to be grippingly retained thereon. Theopposite end 32 of outer tubular sleeve 12 is press fit into one end 34of collar assembly 16. The inner tubular sleeve 18 is sized so as to bereceivable and telescopically movable within outer tubular sleeve 12 andis typically formed from metallic material and is preferably hexagonalin cross-section, however, the configuration of this sleeve 18 can bepolysided, such as square or octagonal. A plurality of apertures 36 isprovided in a spaced-apart relationship along one surface of the innertubular sleeve 18. End cap 20 has a configuration complementary to innertubular sleeve 18 permitting it to be received within end 38 of innertubular sleeve 18 and to be retained therein by a fastener 40 whichpasses through the inner tubular sleeve 18 and into end cap 20. End cap20 has a circular flanged surface 42 at one end thereof. Flanged surface42 has an outer diameter slightly less than the inner diameter of theouter tubular sleeve 12. Threaded connector 22 is received within theopposite end 44 of inner tubular sleeve 18 and is retained therein byoppositely disposed fasteners 46 which are threadably received throughthe inner tubular sleeve 18 and into the body of threaded connector 22.Threaded connector 22 has a threaded end 48 which is received in acomplementary female threaded connector provided in the end of thehandle for a paint roller frame (not shown).

[0024] Collar assembly 16 is comprised of a collar member 50, a bottomtrigger member 52, a top trigger member 54 and a locking pin 56 (shownin FIG. 2). Referring now to FIG. 2, which is cross-sectional view ofthe collar member 50 and illustrates its attachment to the outer tubularsleeve 12 and the position of the inner tubular sleeve 18 within same,collar member 50 is generally circular in cross-section and is comprisedof an end portion 58, a first bore portion 60 and a second bore portion62. End portion 58 has a bore 64 therethrough having a configurationcomplementary to the configuration of the inner tubular sleeve 18, i.e.,if inner tubular sleeve 18 is hexagonal in shape, bore 64 in end portion58 will be similarly hexagonal in shape and will be sized slightlylarger than inner tubular sleeve 18 permitting inner tubular sleeve 18to be telescopically movable within outer tubular sleeve 12. Thecomplementary configurations of inner tubular sleeve 18 and bore 64 inend portion 58 prevents the inner tubular sleeve 18 from rotatingrelative to collar assembly 16 and outer tubular sleeve 12. First boreportion 60 has a diameter slightly less than the diameter of the secondbore portion 62. The diameter of second bore portion 62 is slightly lessthan the outer diameter of the outer tubular sleeve 12 permitting end 32of outer tubular sleeve 12 to be press fit within second bore portion 62of collar member 50 and to be grippingly retained within same. Outertubular sleeve 12 is received and positioned within collar member 50such that its end 32 abuts shoulder 66 defined by the junction of firstbore portion 60 with second bore portion 62 of collar member 50.

[0025] Bottom trigger member 52 is formed from moldable plastic materialand is generally U-shaped in configuration, as shown in FIGS. 3 and 4,and has a pair of spaced apart projections or ears 80 on the innersurface 82 and adjacent each outer end 84 thereof. An inwardly directedlip 86 is located on the inner surface 82 of bottom trigger member 52and is positioned between each pair of ears 80. The outer surface 88 ofbottom trigger member 52 is provided with a flattened surface 90 forplacement of the user's thumb in order to facilitate depressing bottomtrigger member 52 to adjust the overall length of extension pole 10, ashereinafter described. The top trigger member 54 is generally circularin configuration, as shown in FIGS. 5 and 6, with a tab 100 adjacenteach outer end 102 thereof. An angularly extending gap 104 is providedbetween the ends 106 of the tabs 100. A recess 108 that is sized so asto receive an ear 80 on bottom trigger member 52 is provided on eitherside of each tab 100. In addition, an elongated recess 110 that is sizedso as to receive inwardly directed lip 86 on bottom trigger member 52 isprovided in each tab 100. Locking pin 56 is provided within a blind bore112 in the inner surface 114 of top trigger member 54 and is positionedso as to be substantially oppositely disposed to angularly extending gap104. Alternatively, locking pin 56 can be received within a through bore(not shown) in top trigger member 54 and can be positioned and retainedtherein so as to be substantially oppositely disposed to angularlyextending gap 104. The end 116 of locking pin 56 is chamfered, as shownin FIG. 7, providing a pilot or guiding surface for same.

[0026] The top trigger member 54 is formed from a flexible plasticmaterial and has an inner diameter slightly less than the outer diameterportion 120 of collar member 50 which is positioned adjacent first boreportion 60 thereof, as shown in FIG. 2. In this manner, the top triggermember 54 can be slipped over outer diameter portion 120 of collarmember 50 and is grippingly retained thereon. The diameter of outerdiameter portion 120 is slightly less than the immediately adjacentdiameters of end portion 58 and second bore portion 62 of collar member50 forming shoulders 122 and 124, respectively, which minimize thepossibility of any foreign material becoming entrapped between triggermembers 52, 54 and outer diameter portion 120 of collar member 50. Outerdiameter portion 120 of collar member 50 has a bore 126 therethrough forreceipt of locking pin 56 in top trigger member 54. Bore 126 is alignedwith apertures 36 in inner tubular sleeve 18. After top trigger member54 has been received on outer diameter portion 120 of collar member 50,bottom member trigger member 52 is press fit into top trigger member 54causing each oppositely disposed ear 80 on each end 84 of bottom triggermember 52 to be received within a complementary elongated recess 108 ontop trigger member 54 and also causing inwardly directed lip 86 adjacenteach end 84 of bottom trigger member 54 to be received within itscomplementary elongated recess 110 provided in tab 100 on top member 54,as shown in FIG. 7. In this manner, the ears 80 and the inwardlydirected lip 86 on the bottom trigger member 52 interlock with thecomplementary recesses 108 and 110 on top trigger member 54 causing thebottom trigger member 52 and the top trigger member 54 to be joined andmove as a unit. In addition, since top trigger member 54 grippinglyengages outer diameter portion 120 of collar member 50 and since bottomtrigger member 52 is U-shaped rather than circular in configuration, theinterlocking engagement of these members causes a gap 128 to be createdbetween the inner surface 82 of bottom trigger member 52 and theadjacent surface defining the outer diameter portion 120 of collarmember 50.

[0027] In order to adjust the length of the extension pole 10, thesurface 90 on bottom trigger member 52 is pressed laterally inwardlyagainst outer tubular sleeve 12 causing the gap 128 to close and causingthe top trigger member 54, which is formed from flexible plasticmaterial, to move laterally outwardly with respect to collar member 50resulting in locking pin 56 in top trigger member 54 being retractedfrom aperture 36 in inner tubular sleeve 18 through bore 126 in outerdiameter portion 120 of collar member 50. The distance of lateralmovement of the trigger members 52, 54 is less than the height ofshoulders 122, 124 on collar member 50 minimizing the possibility of anyforeign material passing between the trigger members 52, 54 and theshoulders 122, 124 and becoming entrapped between the trigger members52, 54 and the outer diameter portion 120 of the collar member 50. Theinner tubular sleeve 18 can then be telescopically adjusted within outertubular sleeve 12 until the approximate desired length of the extensionpole 10 has been attained. If the bottom trigger member 52 is thenreleased, the gap 128 opens causing the top trigger member 54 to movelaterally inwardly with respect to collar member 50 resulting in thechamfered end 116 of locking pin 56 contacting the outer surface ofinner tubular sleeve 18. Further telescopic adjustment of inner tubularsleeve 18 within outer tubular sleeve 12 causes the locking pin 56 to bereceived within the closest aperture 36 provided within the innertubular sleeve 18 resulting in the inner tubular sleeve 18 being lockedwithin the outer tubular sleeve 12 at the approximate desired length ofthe extension pole 10. (The chamfered end 116 of locking pin 56 acts asa pilot or guiding surface which assists in the receipt of the lockingpin 56 in the closest aperture 36.) The circular flanged surface 42 onend cap 20 prevents the inner tubular sleeve 18 from being inadvertentlyremoved from within the outer tubular sleeve 12 during the telescopicadjustment process. In this manner, the length of the extension pole 10can be easily adjusted and, when adjusted, the length is retained by thelocking pin 56 in the top trigger member 54 being received in theappropriate aperture 36 in the inner tubular sleeve 18.

[0028] The locking mechanism of the present invention provides a numberof advantages over prior art locking mechanisms. For example, thelocking mechanism utilizes a minimum number of components which, becauseof their design, makes the locking mechanism less susceptible to paintbeing entrapped therein. In addition, the components comprising thelocking mechanism (bottom trigger member 52, top trigger member 54 andlocking pin 56) are relatively inexpensive and easy to produce andassemble. Also, the components comprising the locking mechanism are verydurable, however, they can be easily replaced, if necessary.

[0029] An alternate embodiment of the locking mechanism of the presentinvention is shown in FIGS. 8 through 11 which illustrate a collarassembly 130 (locking mechanism) attached to the end of the outertubular sleeve 12 of the extension pole 10. In this embodiment, thecollar assembly 130 is comprised of a collar member 132 and a triggermember 134 having a locking pin 136 therein. The trigger member 134 isof a one-piece, rather than a two-piece, construction, is formed fromflexible plastic material, and is received over the collar member 132.The outer portion of trigger member 134 is generally oval inconfiguration, but its inner portion, shown generally by the numeral138, is circular in configuration. The inner portion 138 of the triggermember 134 has a circumferential slot 140 therein which terminates in aU-shaped slot 142 defining circumferential tangs 144. The trigger member134 is positioned on the collar member 132 such that the inner portion138 grippingly engages the outer diameter of the collar member 132permitting the locking pin 136 to be positioned within a bore 146 incollar member 132 and received in an aperture 36 in inner tubular sleeve18. The circumferential slot 140, U-shaped slot 142 and circumferentialtangs 144 in the inner portion 138 provide flexibility to the innerportion 138 of the trigger member 134 permitting lateral outwardmovement of the trigger member 134 with respect to the collar member132. In order to adjust the overall length of the extension pole 10,surface 148 on trigger member 134 is pressed inwardly, as shown in FIG.11, causing trigger member 134 to move laterally outwardly with respectto collar member 132 resulting in locking pin 136 being retractedthrough bore 146 in collar member 132. The inner tubular sleeve 18 canthen be telescopically adjusted within outer tubular sleeve 12 until theapproximate desired length of the extension pole 10 has been attained.If the trigger member 134 is then released, the trigger member 134 willmove laterally inwardly causing the locking pin 136 to be received inthe closest aperture 36 provided in inner tubular sleeve 18 resulting ininner tubular sleeve 18 being locked within the outer tubular sleeve 12at the approximate desired length of the extension pole 10.

[0030] Certain modifications and improvements will occur to thoseskilled in the art upon reading the foregoing. It should be understoodthat all such modifications and improvements have not been expressly setforth herein for the sake of conciseness and readability, but areproperly within the scope of the following claims.

I claim:
 1. A locking mechanism for a pair of inner and outertelescoping members comprising a collar member having a longitudinallyextending opening therein permitting the receipt of said collar memberon said outer telescoping member and having an aperture therethroughintersecting said longitudinally extending opening, and a trigger membersubstantially encircling said outer telescoping member and having anopening therethrough permitting the receipt of said trigger member onsaid collar member and having a locking pin therein, said locking pinbeing received through said aperture in said collar member and into saidinner and outer telescoping members to lockingly engage said inner andouter telescoping members together.
 2. The locking mechanism as definedin claim 1 wherein a portion of the surface defining said opening insaid trigger member grippingly engages the surface defining said collarmember and the remaining portion of the surface defining said opening insaid trigger member is in a spaced apart relationship with the remainingportion of the surface defining said collar member allowing lateralmovement of said trigger member with respect to said collar member. 3.The locking mechanism as defined in claim 2 wherein outwardly directedlateral movement of said trigger member with respect to said collarmember causes said locking pin to be retracted within said aperture insaid collar member releasing said inner and outer telescoping membersfrom locking engagement permitting relative movement between said innerand outer telescoping members.
 4. The locking mechanism as defined inclaim 1 wherein said trigger member is comprised of a first triggermember portion and a second trigger member portion joined together in aninterlocking relationship.
 5. The locking mechanism as defined in claim4 wherein said first trigger member portion is substantially circular incross-section and grippingly engages said collar member.
 6. The lockingmechanism as defined in claim 4 wherein said locking pin is operativelyattached to said first trigger member portion and is directed radiallyinwardly thereof.
 7. The locking mechanism as defined in claim 4 whereinsaid first trigger member portion has a tab portion provided adjacenteach end thereof.
 8. The locking mechanism as defined in claim 7 whereinsaid first trigger member portion has an elongated slot provided in eachof said tab portions.
 9. The locking mechanism as defined in claim 4wherein said first trigger member portion has at least one recessprovided adjacent each end thereof.
 10. The locking mechanism as definedin claim 4 wherein said first trigger member portion has a tab portionprovided on each end thereof and a recess provided adjacent to and oneither side of said tab.
 11. The locking mechanism as defined in claim10 wherein said first trigger member portion has an elongated slotprovided in each of said tab portions.
 12. The locking mechanism asdefined in claim 4 wherein said second trigger member portion issubstantially U-shaped in configuration causing a portion of the innersurface thereof to be in a spaced-apart relationship with a portion ofthe surface defining said collar member.
 13. The locking mechanism asdefined in claim 4 wherein said second trigger member portion has atleast one projection provided adjacent each end thereof.
 14. The lockingmechanism as defined in claim 4 wherein said second trigger memberportion has an inwardly directed elongated lip provided on the innersurface thereof and adjacent each end thereof.
 15. The locking mechanismas defined in claim 4 wherein said first trigger member portion has atab portion provided adjacent each end thereof, said tab portion havingan elongated slot therein, and said second trigger member portion has aninwardly directed elongated lip provided on the inner surface thereofand adjacent each end thereof, each of said inwardly directed elongatedlips on said second trigger member being received within said elongatedslot in said tab portion of said first trigger member portion when saidfirst and second trigger member portions are in an interlockingrelationship.
 16. The locking mechanism as defined in claim 4 whereinsaid first trigger member portion has at least one recess providedadjacent each end thereof and said second trigger member portion has atleast one projection provided adjacent each end thereof, said at leastone projection on said second trigger member portion being receivedwithin said at least one recess on said first trigger member portionwhen said first and second trigger member portions are in aninterlocking relationship.
 17. The locking mechanism as defined in claim4 wherein said first trigger member portion has a tab portion providedadjacent each end thereof and at least one recess provided adjacent eachsaid tab portion, said tab portion having an elongated slot therein, andsaid second trigger member portion has at least one projection providedadjacent each end thereof and an inwardly directed elongated lipprovided on the inner surface thereof and adjacent each end thereof,said at least one projection on said second trigger member portion beingreceived within said at least one recess on said first trigger memberportion and each of said inwardly directed elongated lips on said secondtrigger member portion being received within said elongated slot in saidtab portion of said first trigger member portion when said first andsecond trigger member portion are in an interlocking relationship. 18.The locking mechanism as defined in claim 1 wherein said collar memberis attached to the end of said outer telescoping member.
 19. The lockingmechanism as defined in claim 1 wherein said trigger member is comprisedof an inner member portion and an outer member portion which are joinedtogether over a portion of their respective peripheries.
 20. The lockingmechanism as defined in claim 19 wherein said inner member portion issubstantially circular in cross-section and grippingly engages saidcollar member.
 21. The locking mechanism as defined in claim 19 whereinsaid locking pin is operatively attached to said inner member portionand is directed radially inwardly thereof.
 22. The locking mechanism asdefined in claim 19 wherein said outer member portion is substantiallyoval in configuration causing a portion of the inner surface thereof tobe in a spaced-apart relationship with a portion of the surface definingsaid collar member.
 23. The locking mechanism as defined in claim 19wherein said outer member portion substantially surrounds said innermember portion.
 24. The locking mechanism as defined in claim 23 furtherincluding a slot interposed between said inner member portion and saidouter member portion permitting lateral movement of said inner memberportion with respect to said collar member allowing said locking pin tobe retracted within said aperture in said collar member releasing saidinner and outer telescoping members from locking engagement allowingrelative movement between said inner and outer telescoping members. 25.The locking mechanism as defined in claim 24 wherein said slot issubstantially U-shaped in configuration.